The different purification methods.

Spring water – natural spring water bottled at the source like ESKA, which is bottled instantly, needs no further purification to be safe to drink.

However, spring water that sits in tanks or has been transported before bottling, is at risk of bacterial contamination.

Municipal water – water from lakes and rivers needs to be processed to be safe to drink.

Distillation – steam from boiling water recondensed and bottled. Although the boiling process kills microbes, it also removes the natural minerals, making it tasteless and reduces its health value.

Deionization – also known as demineralization, uses ion exchange resins to bind to and filter out minerals. The results of this artificial process are similar to distilled water.

Micron Filtration – water is filtered through microscopically tiny holes to get rid of contaminants and microbes.

Ozonation – by adding ozone gas, water is disinfected, which kills most microbes. This process, however, has been linked to bromate, which is a health concern.

Reverse osmosis – water is forced through a membrane using high pressure to filter out microbes, chemicals and all minerals.

Ultraviolet light – water is passed through UV light, killing most contaminants.

Chlorination – the disinfectant chlorine is added to the water supply by municipalities. Although chlorine kills pathogens effectively, there are health concerns with byproducts of the process called trihalomethanes (THMs). Note: some bottled waters that filter with reverse osmosis also use chlorine.